Ina passenger car, e.g., a railcar utilized by the general public, an air-conditioning duct is provided at the ceiling portion of the railcar in a longitudinal direction of the railcar, that is, in a vehicle length direction. Conditioned air which is temperature-regulated by an air-conditioning apparatus is discharged into the air-conditioning duct, and is then discharged into an inside of the railcar from the air-conditioning duct in order to regulate the temperature in the inside of the railcar which is an interior.
Of course, the temperature distribution in the interior is preferably uniform throughout the interior in the vehicle length direction. Therefore, as disclosed in e.g., Patent Document 1, conventionally, the temperature-regulated conditioned air is discharged from the air-conditioning duct at a uniform airflow volume throughout the inside of the railcar. The temperature distribution in the inside of the railcar can thus be uniform.